Niemeyer–Dolan technique

The evaporation mask can be formed from two or more layers of resist, to allow creation of the extreme undercut needed.

Depending on the evaporation angle, the shadow image of the mask is projected onto different positions on the substrate.

By carefully choosing the angle for each material to be deposited, adjacent openings in the mask can be projected onto the same spot, creating an overlay of two thin films with a well-defined geometry.

[4] Additionally, this allows the substrate to be kept under high vacuum, as there is no need to increase pressure to switch between multiple masks.

[4] The Niemeyer–Dolan technique is used to create multi-layer thin-film electronic nanostructures such as quantum dots and tunnel junctions.

Niemeyer–Dolan technique for the fabrication of single electron transistors . (a) Side view, cut along the current path. (b) Side view, cut perpendicular to the current path, and showing the resist mask and the layers deposited on it during the evaporations (changing its cross section). (c) Top view, indicating the cut planes for views a and b.